1. Field of the Invention
The present invention relates to a focus detection apparatus and a control method for the same, and more particularly to a focus detection apparatus that sets a focus detection area to a specific subject region within an image and a control method for the same.
2. Description of the Related Art
In the autofocus (AF) control of video cameras and the like, a TV-AF system that detects an in-focus position based on the sharpness (contrast) of image signals generated using an image sensor is widely used. The TV-AF system, specifically, is a system that generates AF evaluation values indicating the degree of contrast for image signals picked up at different focus lens positions, and searches for a position of the focus lens at which contrast is maximized based on the AF evaluation values as an in-focus position.
Also, image pickup apparatuses having a function of detecting a specific subject in order to stably focus on a human subject in the case of picking up an image of a person are known. For example, an image pickup apparatus that performs focus detection after setting a focus detection area that includes a recognized face region has been proposed (Japanese Patent Laid-Open No. 2006-227080).
In the case of bringing a person's face into focus, focus detection is performed after setting a focus detection area that encompasses a detected face region, as shown in FIG. 8. When, however, a face region cannot be detected in the case of the person having his or her back turned or because of the person wearing a hat, holding a hand over their face, or the like, an appropriate focus detection area cannot be maintained.